Graphs with differnet amounts of data

Hi,

I have tried follow the guidlines on the website http://peltiertech.com/Excel/Charts/Dynamics.html under the Chart the Last 12 Months Dynamically part.

However it hasnt quite worked for me - i have attached a copy of what i have done. I think i can see what has gone wrong, it is looking upwards for data, rather than downwards but i do not know how to fix it

Any help would be appreciated

Thanks

Antony